Value of postirradiation screening for thyroid nodules. A controlled study of recalled patients.

We determined the occurrence of palpable thyroid abnormalities in 214 persons with verified history of head and neck irradiation and in 243 concurrently examined, nonirradiated persons (control subjects). Examinations were performed by two physicians, each unaware of the medical history of the examinees and of the findings of the other examiner. Thyroid nodules, either single or multiple, occurred in 6.1% of irradiated persons and in 4.5% of control subjects (95% confidence interval of the difference, -2.6% to +5.7%). Thyroid enlargement without nodules occurred in 5.6% of irradiated persons and in 3.7% of control subjects (95% confidence interval of the difference, -2.0% to +5.8%). Thyroid cancer was detected in one irradiated and in two nonirradiated persons. Our controlled study did not find an excess number of thyroid abnormalities in previously irradiated subjects.